BMI formula and ranges
BMI is calculated by dividing body weight in kilograms by height in metres squared. For most adults: below 18.5 is described as underweight, 18.5 to below 25 as a healthy range, 25 to below 30 as overweight, and 30 or higher as an obesity range.
Important context
BMI does not directly measure body fat, muscle mass, fitness or overall health, and is less informative for children, pregnant people, older adults and highly muscular people. A clinician can help interpret the number alongside other measurements.
This page is for general information only and is not a diagnosis or medical advice. Speak with a qualified health professional for personal health concerns.